1. Field of the Invention
The invention relates to a motor operator for opening and closing a mains switch of switchgear in mains power distribution systems such as public medium high voltage distribution systems.
2. Description of the Prior Art
Motor operators for switchgears are known see, e.g., U.S. Pat. No. 4,804,809 to Chance Co. AB, U.S. Pat. No. 5,254,814 to Chance Co. AB, WO 2008/052548 A1 to Linak A/S, and WO 2006/106364 to Viserge Ltd. These motor operators are separate units for mounting in front of switchgears as indicated in U.S. Pat. No. 4,804,809 to Chance Co. AB and WO 2006/106364 to Viserge Ltd. The motor operators are contained in a weather- and vandal-proof enclosure which is rather voluminous. Further, it should be fully operable under all weather conditions and operate in a reliable manner. The front surface of the switchgear is exposed to the open air, which is why the overall size of the motor operator is of no significant importance. However, there are also switchgears where the front surface is covered by a front door to protect the front surface of the switchgear and to prevent unauthorized access to the switchgear. The front door restricts the space available for a motor operator, and not only that, it also complicates the mounting as it is prohibited to make bores and weldings in the switchgear cabinet.
It should also be taken into account that the motor 35 operator may be activated either locally or remotely to open and close the mains switch of the switchgear. However, as a safety precaution it should also be possible to operate the switchgear manually, e.g., in case of failure of the motor operator. This also complicates the construction of the motor operator and contributes to the overall size.
Hence, there is a need for a motor operator which overcomes these and other problems associated with the known motor operators.